• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.1
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• pp.44-49
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• 2017

본고에서는 열유도 적외선 열화상 기법의 원리와 응용에 있어 기초적인 개념, 특정 상태량 및 실험적 기법에 대하여 소개하도록 한다. 유도 열화상 기법에 적용되는 유도 주파수의 범위는 1500 Hz ~ 52 MHz이며 강자성 강재 단조 부품의 표면결함 검출에 사용되어진다. 균열 검출 감도는 자분탐상기법과 유사하나 필요한 경우 유도 주파수를 낮춤으로서 강재에 숨겨진 결함을 검출할 수 있다. 탄소섬유강화폴리머(CFRP)에서는 섬유 결함을 검출하며, 실리콘 태양 전지에서는 양호한 열적 콘트라스트와 함께 균열을 검출한다. 유도 열화상 기법의 향 후 대표적인 활용분야로는 레일 및 휠과 같은 철도 구성요소에서의 결함 탐상이 있다[1].

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.330-335
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• 2013

Since real-time monitoring system like a fault early detection has been very important, infrared thermography technique as a new diagnosis method was proposed. This study is focused on the damage detection and temperature characteristic analysis of ball bearing using the non-destructive infrared thermography method. In this paper, for the reliability assessment, infrared experimental data were compared with the frequency data of the existing. As results, the temperature characteristics of ball bearing were analyzed under various loading conditions. Finally it was confirmed that the infrared technique was useful for real-time detection of the bearing damages.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.323-329
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• 2013

This perform research of angle rated defect detection conditions and nuclear power plant piping defect detection by lock-In infrared thermography technique. Defects were processed according to change for wall-thinning length, Circumference orientation angle and wall-thinning depth. In the used equipment IR camera and two halogen lamps, whose full power capacitany is 1 kW, halogen lamps and target pipe's distance fixed 2 m. To analysis of the experimental results ensure for the temperature distribution data, by this data measure for defect length. Reliability of lock-In infrared thermography data is higher than Infrared thermography data. This through research, Shape of angle rated defect is identified industry place. It help various angles defect detection in the nuclear power plant in operation.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.525-531
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• 2004

In this paper, the concept of infrared thermography(IRT), the principle of measurement of IRT and how to set up the IR camera for the nondestructive testing are described in detail. Also, its utilization and non-destructive testing(NDT) diagnosis are reviewed. By performing the periodic non-touched WDT through the estimation of thermal patterns related with the temperature for the surface targeted, IRT can be applied to the early prevention of the device failure. For the diagnosis utilization, thermal imaging patterns obtained from IRT for heated blocks with internal defects were estimated through the lion-destructive method and discussed the way of IRT estimation from the analysis of characteristics between material defects and thermal imaging patterns.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.5
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• pp.341-348
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• 2015

Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.12-19
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• 2012

This study conducted infrared (IR) thermography tests using pipe and plate specimens with artificial wall-thinning defects to find an optimal condition for IR thermography test on the wall-thinned nuclear piping components. In the experiment halogen lamp was used to heat the specimens. The distance between the specimen and the lamp and the intensity of halogen lamp were regarded as experimental parameter. When the distance was set to 1~2 m and the lamp intensity was above 60 % of full power, a single scanning of IR thermography detected all artificial wall-thinning defects, whose minimum dimension was $2{\Theta}=90^{\circ}$, d/t=0.5, and $L/D_o=0.25$, within the pipe of 500 mm in length. Regardless of the distance between the specimen and the lamp, the image of wall-thinning defect in IR thermography became distinctive as the intensity of halogen lamp increased. The detectability of IR thermography was similar for both plate and pipe specimens, but the optimal test condition for IR thermography depended on the type of specimen.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.2
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• pp.134-138
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• 2011

Fault detection for dynamic loading conditions of rotational machineries was considered from the contactless, non-destructive infrared thermographic method, rather than the traditional diagnosis method. In this paper, by applying a rotating deep-grooved ball bearing, passive thermographic experiment was performed as an alternative way proceeding the traditional fault monitoring. In addition, the thermographic experiments were compared with the vibration spectrum analysis to evaluate the efficiency of the proposed method. Based on the results, it was concluded the temperature characteristics of the ball bearing under dynamic loading conditions were analyzed thoroughly.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.3
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• pp.193-199
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• 2015

Active thermography techniques have the capability of inspecting a broad range simultaneously. By evaluating the phase difference between the defected area and the healthy area, the technique indicates the qualitative location and size of the defect. Previously, the development of the defect detection method used a variety of materials and the test specimen was done. In this study, the proposed technique of lock-in is verified with artificial specimens that have different size and depth of subsurface defects. Finally, the defect detection capability was evaluated using comparisons of the phase image and the amplitude image according to the size and depth of defects.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.7-11
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• 2012

For fault detection about the abrasion stage of rotational machineries under the dynamic loading conditions unlike the traditional diagnosis method used in the past decade, the infrared thermographic method with its distinctive advantages in non-contact, non-destructive, and visible aspects is proposed. In this paper, by applying a rotating deep-grooved ball bearing, passive thermographic experiments were conducted as an alternative way to proceeding the traditional fault monitoring on spectrum analyzer. As results, the thermographic experiment was compared with the traditional vibration spectrum analysis to evaluate the efficiency of the proposed method. Based on the results obtained as NDT, the temperature characteristics and abnormal fault detections of the ball bearing according to the abrasion stage were analyzed.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.97-104
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• 2014

Recently infrared cameras have been widely used to diagnosis degradation status of the power substitution system. At the place of high magnetic field, however, electronic parts of infrared camera take a place problem that is not reasonable working due to high magnetic field. In this paper, technique of design for reflector is proposed to perform degradation diagnosis without damage of infrared camera in a power substation system including the rectifier that is able to impact to the infrared camera by high magnetic field.